Synthesis of polycyclic hydrocarbon high-density aviation fuel via one-pot alkyation/hydrogenation by acetic acid modified HY-20 and Pd/C

Biodegradation of sediment-bound PAHs in field-contaminated sediment

Mechanistic insights into organic acid-enhanced polycyclic aromatic hydrocarbon release from soil: Disruption of metal cation bridges and charge-assisted hydrogen bonds.

Effects of various binary and ternary supercritical phases on the extraction of polycyclic aromatic hydrocarbons from contaminated soils

Polycyclic aromatic hydrocarbons (PAHs) are a large class of organic compounds containing two or more fused aromatic rings. They have very low water solubility and are highly lipophilic. Acetic acid is a polar protic solvent that is often used in reactions involving carbocation intermediates. In this study, acetic acid, coupled with other organic solvents, was optimized and used for the extraction of eleven PAHs in two types of foods: toasted and fried. The UHPLC- -DAD method, coupled with a C18 column, was validated and applied to analyze eleven PAHs in the food samples. The LOD and LOQ values obtained ranged from 0.0049 to 0.373 ?g L-1. The recoveries of the PAHs ranged from 47.3 to 119.7 %. The analysis results show that light PAHs were commonly found in both types of food. Some fried foods are highly carcinogenic due to the presence of BaP and Group 2B PAHs. Generally, toasted foods are safe to consume.

Polycyclic Aromatic Hydrocarbons (PAHs) are complex and widely distributed environmental pollutants that can affect living ecosystems. This study was conducted to rapidly degrade phenanthrene and pyrene representing low and high molecular weight of PAHs, respectively. Cronobacter sakazakii MM045 (KT933253) was identified from used engine oil of contaminated soil. PAHs biodegradation was carried out using 2,6-dichlorophenol indophenol (DCPIP) assay. Biodegradation influencing factors including agitation, temperature, pH, inoculums volume and salinity were enhanced using Response Surface Methodology (RSM) by Central Composite Design (CCD). Phenanthrene and pyrene biodegrading metabolites were identified using gas chromatography mass spectrophotometer (GCMS).•Initial biodegradation indicated 75.2% and 54.3% phenanthrene and pyrene degraded by C. sakazakii MM045 within 24h. After CCD optimisation, 100% degradation was achieved for each of the phenanthrene and pyrene, resulting in the formation of intermediate metabolites.•The identified phenanthrene metabolites were 3,4-dihydroxyphenathrene, phthalic acid, pyruvic acid, acetic acid and oxalic acid. Pyrene intermediates comprised pyrene cis-4,5-dihydrodiol, 3,4-dihydroxyphenanthrene, phthalic acid, pyruvic acid, acetic acid and lactic acid.•Cronbacter sakazakii MM045 was proven to be rapid and effective in degrading PAHs within 24h despite the unavailability of existing literatures on PAHs biodegradation.

We previously reported the efficiency of polyamide column in the concentration of polychlorodibenzo-p-dioxins (PCDDs) from environmental water samples. This study further applied the polyamide column to concentrate of the other organic compounds causing the pollution of waters : polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs) and chlorophenols (CPs) from their aqueous solutions. The model compounds used were : benzo [a] pyrene, anthracene and monotrichloropyrenes (PAHs) ; KC300, KC400 and KC500 (PCBs) ; and 2, 4, 6-trichlorophenol, 2, 3, 4, 6-tetrachlorophenol and pentachlorophenol (CPs). The mixture of these compounds in much higher concentrations compared to their putative environmental existence were quantitatively adsorbed to the polyamide column. The fractional elution of the test compounds from the column was attained with ethanol (PCBs and polar PAHs), dichloromethane (nonpolar PAHs) and 5% acetic acid in dichloromethane (CPs plus PCDDs), in this order. Each fraction could be analyzed by either high performance liquid chromatograph equipped with a fluorescence monitor in the case of PAHs or gas chromatograph with an electron capture detector for PCBs and CPs. The polyamide column will be useful for the analysis of trace amounts of organic pollutants in environmental waters.

ABSTRACTThe aim of our study was to identify organic pollutants found in soil and sediment samples collected within the Jackson, MS metropolitan area. The chemical characterization of the organic compound fractions in soil and sediment samples was carried out by separating the organic fraction using column chromatography (CC) and quantitatively analyzing the polycyclic aromatic hydrocarbons (PAHs), n-alkanes and other organic compounds using gas chromatography–electron impact mass spectrometry (GC–MS). Fifty-six compounds were identified and quantified in the soil samples and 33 compounds were identified and quantified in the sediment samples. The PAHs, n-alkanes and other organic compound profiles in the soil and sediment samples were compared. The percentage contents of the organic compounds in the soil samples were very diverse (from traces to 12.44 ± 1.47%). The compounds present in the highest concentrations were n-alkanes: n-C31 (12.44 ± 1.47%), n-C29 (11.64 ± 1.21%), and n-C33 (8.95 ± 1.08%). The components occurring in smaller quantities (from 1% to 5%) were 2 PAHs (fluoranthene 1.28 ± 0.25%, pyrene 1.16 ± 0.20%), 10 n-alkanes from n-C21 (1.25 ± 0.29%) to n-C32 (2.67 ± 0.52%) and 11 other compounds (e.g., 2-pentanol, 4-methyl (3.33 ± 0.44%), benzyl butyl phthalate (4.25 ± 0.59%), benzenedicarboxylic acid (1.14 ± 0.08%), ethane, 1,1-diethoxy (3.15 ± 0.41) and hexadecanoic acid (2.52 ± 0.34). The soil samples also contained 30 compounds present in concentrations <1% (e.g., anthracene (0.13 ± 0.04%), n-C20 (0.84 ± 0.21%) and acetic acid (0.12 ± 0.04%). The compounds present in the highest concentrations in the sediment samples were PAHs: pyrene (7.73 ± 1.15%) and fluoranthene (6.23 ± 1.07%) and n-alkanes: n-C31 (6.74 ± 1.21%), n-C29 (6.65 ± 0.98%) and n-C27 (6.13 ± 1.09%). The remaining organic compounds were present in smaller quantities (< 5%).

One solution for sewage sludge (SS) management is thermochemical treatment due to torrefaction and pyrolysis with biochar production. SS biochar may contain toxic volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs). This study aimed to determine the process temperature’s influence on the qualitative PAHs emission from SS-biochar and the transformation of PAHs contained in SS. SS was torrefied/pyrolyzed under temperatures 200–600 °C with 1 h residence time. The headspace solid-phase microextraction (SPME) combined with gas chromatography and mass spectrometry (HS-SPME-GC-MS) analytical procedure of VOCs and PAHs emission was applied. The highest abundance of numerous VOCs was found for torrefaction ranges of temperature. The increase of temperatures to the pyrolytic range decreased the presence of VOCs and PAHs in biochar. The most common VOCs emitted from thermally processed SS were acetone, 2-methylfuran, 2-butanone, 3-metylbutanal, benzene, decalin, and acetic acid. The naphthalene present in SS converted to decalin (and other decalin derivatives), which may lead to SS biochar being considered hazardous material.

Effective phenanthrene and pyrene biodegradation using Enterobacter sp. MM087 (KT933254) isolated from used engine oil contaminated soil

The majority of polycyclic aromatic hydrocarbons (PAHs) released to the environment come from anthropogenic sources involving the incomplete combustion of organic compounds. Several techniques are available for the degradation of PAHs. Among the abiotic/biotic processes used to degrade PAHs, an alternative strategy utilizing a primary chemical oxidative step to be combined with a biological was created. The degradation of alpha-methylnaphthalene and benzo[a]pyrene using an advanced oxidation process was optimized over a period of 24 h by varying the ratio of acetic acid to hydrogen peroxide, the compounds that form peroxy acids. The optimization process was performed using sandy and silty-clay sediment types. Gas chromatography equipped with a flame ionization detector was used to determine the varied rates of degradation depending on acetic acid:hydrogen peroxide ratios and the characteristics of the sediment sample. Reduction of 20-90% of alpha-methylnaphthalene and benzo[a]pyrene was observed when 2-5 mL of hydrogen peroxide was used, respectively. A peracetic acid solution (e.g., a commercial form of acetic acid and hydrogen peroxide) was used to compare the results from the peroxy acid experiments. In all the experiments, peracetic acid was more reactive than the combination of acetic acid and hydrogen peroxide. Acetic acid, deionized water, and hydrogen peroxide served as controls and demonstrated minimal degradation over the time course study. Therefore, the use of a peroxy acid process to target electron dense pollutants may have a great utility.

Determination of policyclic aromatic compounds, (PAH, nitro-PAH and oxy-PAH) in soot collected from a diesel engine operating with different fuels

Extraction of polycyclic aromatic hydrocarbons from polluted soils with binary and ternary supercritical phases

Nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) are highly mutagenic and carcinogenic; they can adsorb to air particulates for long-range transport, then enter the aquatic environment through atmospheric deposition. Some personal care products (PCPs), such as analgesics, UV filters, cosmetic preservatives, DEET, and caffeine, are used at a large scale. This study developed and validated an analytical method for analyzing five NPAHs, three OPAHs, and 13 personal care product ingredients in water, sediment and fish tissues (muscle and liver). Analytes in water samples were extracted using PolarPlus C18 disks with high-flow automated solid-phase extraction; sediment, muscle and liver were treated with matrix solid-phase dispersion (MSPD) on SiliaBond C18, and eluents of methanol and acetone were directly passed through alumina cartridges for cleanup. After concentrations, the eluents were injected onto ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) with multiple reaction monitoring and analytes were quantified with isotope-dilution techniques. Analytes forming positive ions were separated on a Kinetex PFP column (50 × 2.1 mm, 2.7 μm) using positive electrospray ionization (ESI+) and positive atmospheric pressure photoionization (APPI+), with 10-mM ammonium acetate/0.25% acetic acid(aq) and methanol for gradient elution; analytes forming negative ions were separated on a CORTECS C18 column (30 × 2.1 mm, 1.6 μm) using negative ESI (ESI-), and the mobile phases were 0.04% acetic acid(aq) and methanol. ESI provided better signal intensities on all PCPs (2.39-36.8 times higher) than APPI, and was also suitable for analyzing 1-nitropyrene, 2-nitrofluorene and 5,12-naphthacenequinone; however, 7-nitrobenz[a]anthracene and 9-nitroanthracene can only be detected using APPI, and the use of anisole as the dopant offered better signal intensity than that using chlorobenzene and toluene. Each chromatographic separation was less than eight minutes including column re-equilibrium. The extraction efficiency of the analytes from surface water were 61.8-126%.; the extraction efficiency of MSPD on sediment, muscle and liver were 30.6-67.8%, 21.5-70.5%, and 31.8-127%, respectively. Matrix effect factors of surface water and sediment were 21-92.9% and 88.6-147%, respectively; matrix effect factors of from muscle and liver were 75.1-161%, and 31.4-81.7%, respectively, except that acetaminophen were lower than 28% and 10%., respectively. The limits of detection (LODs) of analytes in water ranged from 0.14-6.88 ng/L, and the LODs in sediment, muscle and liver ranged from 0.56-14.7 ng/g wet weight (w.w.), 1.18-23.9 ng/g (w.w.) and 1.13-19.4 ng/g (w.w.), respectively. This study tested method accuracy and precision at three spiked levels, and most of the quantitative biases and relative standard deviations were lower than 30% and 25% on water samples, respectively; most of those on sediment, muscle and liver samples were lower than 20% and 15% respectively. This method was applied to investigate the NPAHs/OPAHs and PCPs in river water, sediment and tilapia (Oreochromis spp.) in the Kee-Lung River, Taipei. Acetaminophen, ibuprofen, ketoprofen, naproxen, oxybenzone, benzophenone, caffeine, and DEET were detected in all of the water samples; the most abundant analytes were caffeine (506 ± 751 ng/L, n = 6) and DEET (119 ± 44.3ng/L, n = 6), respectively. Caffeine, oxybenzone, benzophenone, methyl paraben and ketoprofen were detected in all sediment samples; benzophenone was the most abundant compound (258 ± 64.8 ng/g w.w., n =6). Acetaminophen, DEET, benzophenone, methyl paraben and ketoprofen were detected in most of fish tissues. Benzophenone was the the highest among the analytes in fish muscle (132 ± 46.4 ng/g w.w., n = 15), and acetaminophen (325 ± 162 ng/g w.w., n = 15) was the highest in liver. Analgesics, UV filters and DEET in fish liver were found to be higher than that in muscle, but caffeine and methyl paraben tended to accumnlate in muscle. The NPAHs and OPAHs were not detected in water, sediment and fish tissues. According to bioaccumulation factors (BAFs) of the analytes in our study, benzophenone, oxybenzone, ketoprofen and methyl paraben which have high log Kow, tended to have higher BAFs; however, although acetaminophen and caffeine have much lower log Kow than above analytes, they still had high BAFs in fish muscle and liver. The bioaccumulation of PCPs in fish muscle and liver, which implies the potential for entering the food chain, may pose ecological and health risks.

Dependences of the quantity of polycyclic aromatic hydrocarbons (PAH) on the conditions for the formation of components of smoke compositions, the type of wood, the formulation, the technology of production, and the type of packaging material have been studied. An increase in temperature from 450 to 700 °C lead to a 2-3-fold increase in the amount of PAH in meat products. It has been established that the use of a polyamide coating reduced the total carcinogenicity of sausages by 2.0-3.7 fold compared with protein and natural shells, which in terms of PAH accumulation were the most dangerous. Fibrous shell was able to provide a reduction in PAH level in the product up to 40% compared to natural one. The permeability of the fat fraction of the product for PAH was up to 10 fold higher than that of proteins and carbohydrates. The data obtained made it possible to determine the safety criteria for smoked meat products, taking into account the potential carcinogenic hazard of each PAH. The optimal indicators of the presence of PAH in the product are 8 PAH (benz[a]pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, dibenz[a,h]anthracene, indeno[1,2,3-c,d] pyrene). The PAH exposure on the human body has been determined under the constant consumption of smoked meat products. The prospective use of barrier protection technologies, substances possessing antiradical activity, and protective films to reduce residual PAH content has been proved. The results of the studies showed a 5-fold decrease in the total amount of PAH when using films impregnated with fat-containing micro anemulsion of vegetable or animal fat. The effect increased when meat was marinateв in a 9% solution of acetic acid or 3% solution of ascorbic acid.

This study analyzes polycyclic aromatic hydrocarbon (PAH) compounds released from scrap tires by GC/MS and introduces a simple extraction process at ambient conditions to remove PAHs from scrap tires. The PAH species released from scrap tires included seven PAH compounds with high molecular weight and 4- and 5-aromatic rings and total-PAH content of 159 mg/L. When scrap tires were extracted using hot water (180 °C) for 3 h, the overall removal efficiency was 53%, indicating that PAHs were not adequately removed by this method. However, using organic solvents, the overall PAH removal efficiency improved to 82% for propionic acid and 70% for acetic acid, because the mass transfer of PAHs within scrap tires increases with decreasing dielectric constant. The PAH removal efficiency was dependent on solvent type and temperature.